Nutrition

• Nutrients

  Substances that provide nourishment essential for the maintenance of life and for growth
• Nutrients

  • Provides energy and regulates body processes
  • Builds and repairs body tissue
• Categories of nutrients needed for optimal health and wellbeing

  • Carbohydrates
  • Protein
  • Fats
  • Vitamins
  • Minerals
  • Water

  
• Macronutrients

  • Nutrients that is required by the body in large amounts
  • Contain significant amounts of kilojoules (kJ)
  • Larger molecules

  
• Micronutrients

  • Nutrient that is required by the body in small amounts
  • Smaller molecules

  
• Kilojoules (kJ)

  • A unit for measuring energy intake or expenditure
  • 1 calorie = 4.2kJ
• Carbohydrates

  • Its function is to provide fuel for the body
  • Carbohydrates are broken down into glucose
  • Glucose molecules are absorbed into the bloodstream
  • Glucose is the preferred fuel energy in the body
  • 1g of carbohydrate = 16kJ of energy
• Not enough carbohydrates can cause low levels of energy, low concentration levels, constipation and issues with the bowel
• Too much carbohydrates can cause weight gain, obesity, high blood pressure, heart disease and diabetes
• Recommended daily intake (RDI) of carbohydrates

  • 45-60% of total daily kJ intake
  • Intake depends on age, gender, weight, size and daily activity levels
  • Average female: 120-180g
  • Average male: 180-210g
• Carbohydrate food sources

  • Vegetables
  • Rice
  • Bread
  • Pasta
  • Cereals
  • Fruits
  • Sugars
  • Sports drinks

  
• Carbohydrate categories


  • Simple carbohydrates (refined and stripped of their natural state - fruit, honey and milk)
  • Complex carbohydrates (carbs found in whole - wholegrain cereals, vegies, fruit and legumes)
  • Soluble Fibre (dissolves in water - fruit, vegies, lentils, oat bran)
  • Insoluble Fibre (does not dissolve in water and tends to speed the passage of foods through the stomach and intestines - nuts, seeds, wholegrain foods, skin of fruit & vegies)

  
• Glycaemic Index

  It measures the effect that carbohydrate foods have on blood glucose levels and how quickly they cause them to rise (0-100)

  
• High GI foods

  • Those that cause a sharp increase in blood glucose/quickly rises (>70 - white bread, short-grain rice, potatoes, potato chips, watermelon, some breakfast cereals, lollies, sports drinks)

  
• Low GI foods


  • Those that release glucose into the bloodstream more gradually/sustained (<55 - sweet potato, some fruits (apples, pears, oranges), wholemeal breads, nuts, wholemeal spaghetti, yoghurt)

  
• Fibre

  • A type of carbohydrate found in all foods of plant origin
  • Also found in wholegrain foods
  • Travels through the digestive system acting as a cleaner rather than being absorbed by the body

  
• Benefits of fibre


  • Leaves you feeling full
  • Reduces cholesterol levels
  • Absorbs water
  • Prevents constipation
• Soluble Fibre

  • Satisfies hunger (takes longer to digest)
  • Absorbs water in the large intestine which softens faeces making it easier to excrete
• Insoluble Fibre

  • Binds with cholesterol, preventing its absorption
  • Volatile fatty acids are produced as it ferments during digestion which is thought to prevent cancer
• Protein

  • Two main functions: Build, maintain and repair body cells
  • Acts as a fuel for producing energy - secondary source (if they do not have enough glucose)
  • 1g protein = 17kJ
• Excess protein intake may be stored as adipose or fat tissue and can contribute to obesity in the long term
• Not enough protein can cause muscle and lean tissue break down or starvation
• Recommended daily intake (RDI) of protein

  • 10-35% of total daily kJ intake
  • Average female: 60g per day
  • Average male: 75g per day
• Amino acids

  • Proteins are made up of 20 different types of amino acids
  • 9 of these must be consumed and cannot be synthesised by the body
  • Therefore protein from a range if different sources should be eaten
• Protein food sources

  • Animal sources: Eggs, Milk, cheese and other dairy, Beef, Chicken and other poultry, Fish and seafood
  • Plant sources: Soy products
• Fats

  • Also functions as fuel for the body
  • Development and maintenance of cell membranes
  • Cell membranes are responsible maintaining cell structure and transport of nutrients, gases and waste in and out of cells
  • Richer source of energy (1g = 37kJ)
  • RDI: 30% of total kJ intake - Males: 78g, Females: 68g
• Not enough fats in daily intake can cause difficulty in regulating body temperature, no fat stores/emergency energy stores, possible infertility, dry skin and hair
• Too much fat can cause overweight and/or obesity, high blood pressure, breathlessness, heart disease, diabetes
• Types of fats

  • Monounsaturated & Polyunsaturated (healthy type of fats that reduce cholesterol levels, support brain function, promote heart health)
  • Saturated & Trans (known as the bad fats that increase cholesterol levels and contribute to cardiovascular diseases)

  
• Replacing saturated and trans fats with monosaturated and polyunsaturated fats will assist health and wellbeing
• Cholesterol

  • Waxy fat found in saturated fats
  • Required for optimal functioning of the body
  • Excess can lead to blocking of arteries (atherosclerosis)
  • Can be bad (Low density lipoproteins - LDL) or good (High density lipoproteins - HDL)

  
• Monounsaturated fats

  • Liquid at room temperature, solid when cold
  • Assists in lowering low density lipoproteins (LDL) - aka the bad cholesterol
  • Decreases atherosclerosis and cardiovascular disease

  
• Monounsaturated fat food sources

  • Olive oil, Avocado, Canola oil, Peanuts, Cashews, Hazelnuts and Almonds

  
• Polyunsaturated fats

  • Two types: Omega-3 and Omega-6
  • Liquid both at room temperature and when cold
  • Act to lower LDL
  • Increase high density lipoproteins (HDL)
  • Reduces risk of cardiovascular disease
  • Omega 3 promotes elasticity in blood vessels, which prevents blood clots, decreases heart attack and stroke
• Polyunsaturated fat food sources

  • Omega-3: Fish particularly oily fish (Mackerel, trout, sardines, tuna, salmon), canola, soy oils, canola-based margarines
  • Omega-6: Mainly nuts such as walnuts and brazil nuts, seeds, oil made from corn and soy

  
• Saturated fats

  • Often found in animal origin
  • High in cholesterol

  
• Saturated fat food sources

  • Full cream milk, cream and cheese, some fried take away food, commercially baked goods (pastries, biscuits)
• Trans fats

  • Most trans fats created when liquid oil converts to solid fat (hydrogenation)
  • Increase cholesterol levels
  • Increase risk of cardiovascular disease
  • Interfere with cell membranes
  • Contribute to high blood glucose levels
  • Can lead to diabetes mellitus

  
• Trans fat food sources

  • Processed foods such as pies, pastries and cakes
• Water

  • Makes up 50-75% of the body
  • Forms the basis of blood, cells, digestive juices, sweat
  • Is in lean muscle, fat, bones
  • Required for a medium for all chemical reactions in the body
  • Body can't store water - we need fresh supply each day
  • Amount needed depends on body size, metabolism, weather, activity, diet
  • RDI to prevent dehydration: Women 8 cups (2L), Men 10 cups (2.6L)